What is the greatest common factor of $30$ and $50$ ? Another way to say this is: $\operatorname{gcf}(30, 50) = {?}$
Answer: The greatest common factor is the largest number that is a factor of both $30$ and $50$ The factors of $30$ are $1$ $2$ $3$ $5$ $6$ $10$ $15$ , and $30$ The factors of $50$ are $1$ $2$ $5$ $10$ $25$ , and $50$ Thus, the greatest common factor of $30$ and $50$ is $10$. $\operatorname{gcf}(30, 50) = 10$